SportsPhotos Grand Sumo tournament in Tokyo Print Share fbShare Tweet Email Japanese Sumo is an ancient sport dating back some 1,500 years. The first sumo matches were part of a prayer ritual dedicated to the gods for a good harvest season. Original sumo matches combined crude boxing and wrestling techniques before rules were formed to shape it into its current form. Now there are six Grand Tournaments per year held across Japan, each tournament lasting 15 days. The Rikishi (wrestler) strives to move through the ranks to be eligible to win the grand prize, the Emperors Cup. Comments We're revamping our Comments section. Learn more and share your input.